Interactions of weakly coordinating anions with tripalladium sandwich complexes

An understanding of the interaction of weakly coordinating ligands with zero-valent palladium complexes is of importance to understanding the potential catalytic mechanisms and properties of these complexes. We have used a combination of multi-nuclei NMR, microanalysis and single crystal X-ray diffraction to characterize a series of tripalladium ditropylium sandwich complexes that possess one or more triflate [CF3SO3]− ligands. The influence of the strong electronic effects on the triflate ligand cause a significant change in the internal bond lengths and angles of the complexes which are coupled to systematic shifts of the tropylium 1H and 13C resonances in the NMR spectra. The use of the Advanced Light Source (ALS) permitted crystallographic characterization of only the third example of a complex containing a Pd–FBF3 bond.